This invention relates to a sealing gasket for use in a static environment. The gasket is of the type which has a non-metallic basic body for providing a seal between two face-to-face arranged flanges at operating temperatures of over 500.degree. C., for example, for use in exhaust pipes of internal combustion engines.
Sealing gaskets of the above-outlined type are known. They conventionally have a flat basic body of pure graphite or asbestos which is usually reinforced by apertured sheet metal parts or a metal web. Apart from the fact that asbestos is presently sought to be replaced by other materials, these known gaskets have not been able to perform with the required durability and sealing effect in all applications, particularly when used at temperatures well in excess of 500.degree. C. Failure to seal properly is often the result of temperature-caused deformations of the flanges (and tightening bolts), causing a distortion of the originally planar and essentially parallel seating faces between which the gasket is clamped. Such deformations cause the appearance of gaps which, particularly after a longer service period, cannot be filled by virtue of the own elasticity of the sealing gasket.
There are further known gaskets designed for use in angularly movable joints. Such seals have a spherical sealing face which slidably engages a complementally formed counter-face of the joint flange. For these types of uses it is known to wind the gasket body of ribbons constituted by a woven or mesh metal structure which encloses mica material.
It is known that natural mica materials may be split into layers by treating them with reactive solvents, with or without a simultaneous application of higher temperatures. The mica layers or scales (flakes) obtained in such a manner are further pocessed, with the addition of binders, to obtain foils, plates or shaped components which are used, for example, in the electro-industry, particularly if the component is required to preserve its original shape at higher temperatures.
Binder-free mica is further used in an environment of chemically corrosive media as sealing plates or protective layers.
There are further known mica materials such as vermiculite which are expanded to a significantly increased volume at high temperatures. These materials have been used heretofore for secondary purposes such as packaging or heat insulation.